Version: 1.21.1, vanilla and Neoforge
Datapack/mod version: 1.1.13 and 1.1.12
Singleplayer
Mac
I've tried using both Continents as a Neoforge mod and as a datapack individually, and I've generated multiple worlds in singleplayer that don't follow Continents worldgen. While I initially thought it might be a mod compatibility issue, I created a Neoforge instance and a vanilla instance with nothing else to try creating a world with nothing but Continents installed but even then the worldgen didn't work (datapack + vanilla, mod + Neoforge, datapack + Neoforge)
Using /datapack list did confirm that the datapack was loaded, and other datapack based worldgen has worked for me so I have no clue what the issue might be